In recent years, growing interests in environmental issues with the development of data communication equipments have given rise to the development of a variety of sensors for detectin and monitoring biomaterials. And by using semicondutor technologies, the manufacturing process of sensors becomes simple and their performance becomes enhanced. The approach to improve the performance of sensors (e.g. sensitivity) are actively researched in various fields.
Electrochemical sensors and optical sensors are most widely used as biosensing mechanism.
Optical sensors show very fast response on the target analytes and high sensitivity. However, their relatively complex configuration and bulky size limit space utilization and efficient operation.
The limitations of the optical sensors listed above can be overcome by using electrochemical sensing mechanism. The electrochemical sensors measure electrochemical currents flowing through external circuits that are generated in oxidation and reduction reactions of analytes. And the electrochemical sensors also use electromotive force generated at ion electrodes by ions in electrolytes, ionized gases, ions dissolved in solid. However, relatively low sensitivity and slow response time compared to the optical sensors limits extension of their applications.
In the Korean Patent (Registration No. 0741187), an electrochemical sensor that measures a concentration of an analyte measures a concentration of an analyzing target component in an aqueous liquid sample by placing the sample in an electrochemical cell including two electrodes with some impedeance that allow current measurement. By directly or indirectly reacting the analyzing target materials with an oxidation and reduction agent, a material that can be oxidized or reduced is formed to have the amount corresponding to the concentration of the analyzing target component. Subsequently, the amount of the material that can be oxidized or reduced is electrochemically measured. In the aforementioned method, the electrodes need to be sufficiently separated from each other so as not to allow electrochemical products at on electrode to reach the other electrode and thus interference between two electrodes can be minimized during the measurement. Furthermore, manufacturing cost may be high, and a manufacturing process may be complex.